Rotating Fan Illusion

1}When you see a rotating fan, at the start it seems like rotating in opposite direction. Why does it look so? 2}This also happens when the fan is rotating at a very high speed.
In the first case, the illusion stays for few seconds. But in the second case, it remains as long as the fan is rotating. Posted in: #Coffee Room

really a good observation. this is due to something which i explain later inshahallah

mreccentric

1}When you see a rotating fan, at the start it seems like rotating in opposite direction. Why does it look so? 2}This also happens when the fan is rotating at a very high speed.
In the first case, the illusion stays for few seconds. But in the second case, it remains as long as the fan is rotating.

Stroboscopic effect. You will not see it in daylight. Tubelight, which has a high frequency flicker can cause this. Same effect is seen with car wheels or helicopter blades in films.

Bioramani

Any idea why this image looks like it is? It's a image of ceiling fan taken from a movie.
No... i understood why it happens so. Thank You FOR THE ANSWERS of the prev question.

bioramani

Stroboscopic effect.

Bioramani

dear please explain some more about this effect.

Anku2993

dear please explain some more about this effect.

Here is how it works. When the frequency of the light source matches the RPM of the fan it appears stationary.